For many years an effort has been made to provide an emergency brake device for trucks and trailers that is safe, effective and reliable. The situation has become more acute in recent years due to the overcrowding of the interstate highway system, particularly around urban areas. Due to higher speeds, higher gross weights and/or steep downhill grades, existing brake systems in trucks or other heavy vehicles are often inadequate to prevent them from causing accidents. Heavier loads are being allowed on interstate highways, contributing to the increased incidence of accidents involving trucks. One cause of brake failure is glazing. When a truck is negotiating downhill, the driver even if he downshifts before starting downhill must often use his brakes to further slow down the truck, for control around curves, etc. Often the heat build-up exceeds the capacity of present brake systems to dissipate the heat generated, resulting in a set of glazed brake pads and a runaway truck. Glaze renders the brakes totally useless. Another cause of brake failure is failure in the hydraulic or pneumatic system, causing loss of pressure necessary to activate the brake pads. In the event of brake failure, it is almost impossible to avoid an accident often accompanied by serious injuries or loss of life.
A fully loaded tractor-trailer under a panic stop situation often will experience jack-knifing. Under this situation, the trailer skids sideways at a faster rate than the tractor, overrunning the tractor and often causing the entire tractor-trailer to overturn. If the roadway is icy or snow-covered, the tendency of the tractor trailer to jack-knife is magnified many times over.
Prior art braking systems have not been as successful in addressing these problems. Braking systems which depend on activating the brake pads to stop a moving tractor-trailer or large commercial truck have not been satisfactory.
There is therefore a need to provide an emergency brake device for tractor trailers and the like that would stop the vehicle during a panic stop without jack-knifing even when the road is slippery.